1. Field of the Invention
The present invention concerns the sealing between the opening of a bore and a screw and more precisely a method and assembly for providing a seal between the screw and the opening of the bore on which the head of the screw comes to abut.
The invention finds applications in particular in the field of the automobile industry and more precisely for assembling a contactor on a starter support.
2. Description of the Related Art
The method of the invention concerns the production of a seal between the opening of a bore belonging to a support and a screw comprising a head connected to a body provided with a threaded part intended to cooperate with a hole in a piece to be assembled with the support, the support having a lower mechanical strength than the screw.
The document FR 2 509 823 discloses a method for producing a seal between the opening of a bore in a cap molded from a thermoplastic material and a terminal.
Means under the head of the terminal are provided to act on the opening of the bore so that the clamping of the terminal with respect to the cap gives rise to the deformation of the opening by causing flow of the plastic material so that it constitutes a rim that comes to be gripped against the smooth periphery of the body of the terminal.
The means carried by the terminal to deform the opening of the bore are produced in the form of a bevel, constituting the connection between the head and the body of the terminal, this bevel coming to bear against the sharp-angled edge of the bore of the housing.
In a variant, it is the opening of the bore that comprises an external peripheral bead that is pushed back by the flat underside of the head of the terminal with a view to constituting the rim.
This document concerns particularly the sealing of the terminals of the contactor of an electric starter for an internal combustion engine.
The method disclosed in the document FR 2 509 823 applies to a terminal having on the periphery of its body a smooth surface in order to enable the rim to be clamped against this periphery. It is therefore necessary to develop a specific manufacturing method for producing this smooth surface, which may be expensive.
In addition, the method described concerns only a cap molded from thermoplastic material.
Finally, the sealing takes place solely between the rim and the periphery of the smooth part of the terminal.